The present invention relates to an apparatus for connecting hoses for transmission of fluids; more particularly, to so-called xe2x80x9cquick-connectxe2x80x9d connectors wherein a female element grasps and retains a male element to effect a seal therebetween without resort to screw-type loading; and most particularly, to a male/female quick-connect connector including a self-resetting overpressure relief valve.
Connector means for coupling two hoses, or a hose to a bulkhead fitting, are well known. Some such applications benefit from conventional screw-type couplings wherein a female nut on a first coupling element engages a male threaded portion on a second coupling element to draw together mating surfaces therebetween. Such couplings, however, may not be readily connected and disconnected, and may require the cumbersome use of wrenches or other tools. In some other applications, however, it can be highly desirable to employ quick-connect type couplings which can be connected and disconnected manually, quickly, and easily, without tools and without threaded elements.
In one such prior art commercially-available quick-connect connector, a female coupling element is connectable to a first hose and has an axial bore having seal means such as O-rings disposed therein. A tubular male coupling element is connectable to a second hose and has an extension for entering the female axial bore and being sealed therein by the seal means (see SAE Specification J2044). The female element is further provided with a retaining ring containing a plurality of balls which are radially movable and with an axially biased outer sleeve having a tapered inner surface. The male element is further provided with a circumferential ridge and groove for receiving the balls when the two elements are mated. The axially biased sleeve may be manually retracted to permit the balls to move radially outward while passing axially over the ridge to a position adjacent the groove. When released, the sleeve returns axially to a rest position, the tapered inner surface urging the balls radially inward into the groove behind the ridge, and retaining them there, thus coupling the female element onto the male element.
A shortcoming of such a prior art connector in some applications is that the connector maintains the connection at all working pressures to which the application may be subjected. Thus, a hose and coupling system, if subjected to unanticipated overpressure conditions, can fail explosively as by rupture of one of the hoses. Such failure can be anticipated to some extent by installation of a rupture disk in a line fitting, but such a disk cannot reset itself after failure, requiring shutdown of the system, probable drainage thereof, and replacement of the rupture disk. Alternatively, an overpressure valve may be substituted for a rupture disk, which valve may or may not be self-resetting after opening to accommodate an overpressure incident. In either case, an additional valve adds an additional piece of hardware to a hydraulic system and represents an additional possible leak point.
In a specific automotive application, overpressure in a fuel line may result in rupture of the fuel line, presenting a fire hazard if the rupture is external to the fuel tank. In an automotive fuel system, it is desireable to maintain fuel in the feed line when the vehicle is parked so that the engine is easily restarted. In the prior art, a pressure regulator in the feed line prevents overpressurization thereof by regulating the action of the fuel pump, which typically is disposed within the fuel tank. If the regulator fails in a closed position, or the fuel line becomes plugged, then a relief valve incorporated in the fuel pump can prevent overpressure as long as the engine is running. However, when the engine is off and the pump is not energized, residual engine heat can cause the fuel in the feed line to expand. If an additional relief valve is installed in the feed line within the fuel tank but external to the pump, than any leakage in the valve will cause the line to drain into the tank when the engine is shut off, resulting in difficulty in restarting the engine.
What is needed is a connector for a feed line which is readily and positively connected and disconnected, preferably without resort to tools, and which includes relief valve means which is automatically resetting after an overpressure condition is passed.
It is a principal object of this invention to provide improved means for easily coupling two hoses while simultaneously providing automatically resettable relief valve means for relieving an overpressure condition in the hoses.
Briefly described, the present invention is directed to an improved quick-disconnect connector having a female element for connection to a first hose and a male connector for connection to a second hose. As in the prior art, the female element has an axial bore for sealably receiving a tubular portion of the male element. The male element further includes a coil spring that extends into the female element and is attached thereto by a U-shaped clip. The spring is sized to hold the male element axially within the male/female seal means up to a desired inline pressure. When the desired pressure limit is exceeded, the male element is forced axially of the female element until the male/female seal is broken, thereby relieving the overpressure condition. The spring is extended during this action, and when the un-sealing force is relieved the male element is biased back into sealing relationship with the female element, thereby automatically resetting the relief valve means.